RESUMEN
BACKGROUND: Rapid diagnostic test (RDT) of norovirus and rotavirus is commonly used for outbreak screening and patient management. Varying accuracy of the test and cross-reactivity has been reported and could affect the outcome of management. The primary purpose of this study is to provide the accuracy of norovirus and rotavirus rapid diagnostic tests and to analyze the cross-reactivity of both tests. MATERIALS AND METHODS: Stool samples collected from every acute diarrhea patient aged <15 years old who was admitted at Bhumibol Adulyadej Hospital, Bangkok, Thailand, from November 2014 to September 2016 underwent the following test: QuickNaviTM - Norovirus2 for norovirus, VIKIA® Rota-Adeno for rotavirus, and aerobic bacterial culture. Real-time reverse transcription polymerase chain reaction was used as a gold standard for virus detection. False-positive results determined cross-reactivity. RESULTS: From 358 stool specimens, the sensitivity of RDTs for norovirus and rotavirus was 27.5% and 44.8%, respectively. The specificity of RDTs for norovirus and rotavirus was 97.7% and 91.6%, respectively. False positive results of RDT for norovirus occurred in 6 samples (1.7%) and 22 samples (6.1%) in RDT for rotavirus. Rotavirus RDT was found to have cross-reactivity with 11 norovirus infection and 3 bacterial infected stools. CONCLUSION: We found that the RDTs for both rotavirus and norovirus have high specificity but low sensitivity. Cross-reactivity was observed in positive rotavirus RDT with half of it being norovirus.
RESUMEN
Norovirus (NoV) is the leading cause of viral acute gastroenteritis among all age groups in the world. We performed a molecular epidemiological study of the NoVs prevalent in Bangkok between November 2014 and July 2016 to investigate the emergence of new NoV variants in Thailand. A total of 332 stool specimens were collected from hospitalized pediatric patients with acute gastroenteritis in Bangkok, Thailand. NoVs were detected by real-time PCR. The genome of the N-terminal/shell domain was amplified, the nucleotide sequence was determined, and phylogenetic analyses were performed. GII NoV was detected in 58 (17.5%) of the 332 specimens. GII.17, a genotype strain prevalent from 2014 to mid-2015, was hardly detected and replaced by the GII.3 genotype strain. Entire genome sequencing followed by phylogenetic analysis of the GII.3 genotype strains indicated that they are new recombinant viruses, because the genome encoding ORF1 is derived from a GII.12 genotype strain, whereas that encoding ORF2-3 is from a GII.3 genotype strain. The putative recombination breakpoints with the highest statistical significance were located around the border of 3Dpol and ORF2. The change in the prevalent strain of NoV seems to be linked to the emergence of new forms of recombinant viruses. These findings suggested that the swapping of the structural and non-structural proteins of NoV is a common mechanism by which new epidemic variants are generated in nature.